Sliding bearing and method for the manufacture thereof

ABSTRACT

A sliding bearing for axial and/or radial arrangement of a first bearing member in relation to a second bearing member, comprises a second bearing member, which has a bearing recess provided with a second slide face; a first bearing member, which is lodged in the bearing recess and which is mounted axially and/or radially, the first bearing member having a first slide face, which is opposite the second slide face and spaced therefrom by a clearance; at least one sliding/guiding element, which is disposed between the first and the second bearing members and fixed in relation to one bearing member, for guidance of a motion of the first relative to the second bearing member; an equalizing compound, which is disposed between the at least one sliding/guiding element and the bearing member relative to which is fixed the at least one sliding/guiding element, for adaptation of the guide clearance between the at least one sliding/guiding element and the slide face that is displaceable in relation thereto, the equalizing compound being solid in the operating state of the sliding bearing and free-flowing prior thereto.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a sliding bearing for axial and/orradial arrangement of a first bearing member, in particular an interiorpipe, in relation to a second bearing member, in particular an exteriorpipe, as well as to a method of manufacturing the sliding bearing.

[0003] 2. Background Art

[0004] In telescopic structures, several pipes of successivelydecreasing diameter are insertable one into the other. It is of greatimportance that the pipes be slidable substantially free from play,accurately guided along a single central longitudinal axis. Frequently,work tolerances are the reason for the lack of accurate guidance rightfrom the start. Grinding the slide faces for corresponding fit cannot beconsidered because of the cost factor.

SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to embody a slidingbearing at as low a cost as possible that will overcome the prior artdrawbacks.

[0006] This object is attained in a sliding bearing comprising a secondbearing member which has a bearing recess provided with a second slideface; a first bearing member, which is lodged in the bearing recess andwhich is mounted axially and/or radially, the first bearing memberhaving a first slide face, which is opposite the second slide face andspaced therefrom by a clearance; at least one sliding/guiding element,which is disposed between the first and the second bearing members andfixed in relation to one bearing member, for guidance of a motion of thefirst relative to the second bearing member; an equalizing compound,which is disposed between the at least one sliding/guiding element andthe bearing member relative to which is fixed the at least onesliding/guiding element, for adaptation of the guide clearance betweenthe at least one sliding/guiding element and the slide face that isdisplaceable in relation thereto, the equalizing compound being solid inthe operating state of the sliding bearing and free-flowing priorthereto. The sliding bearing according to the invention is manufacturedby a method comprising the following steps: providing a second bearingmember with a bearing recess that comprises a second slide face, and afirst bearing member which is insertable in the bearing recess, having afirst slide face that is allocated to the second slide face; applying acurable equalizing compound, which is free-flowing when worked, to atleast a section of a slide face and/or to the sliding band; placing thesliding band on the equalizing compound; inserting the first bearingmember into the bearing recess of the second bearing member so that theat least one sliding band rests uniformly and planely on the oppositeslide face and the excess equalizing compound is squeezed intoequalizing areas that are provided therefor; curing the equalizingcompound.

[0007] The gist of the invention resides in a sliding element beingprovided between two bearing members that are to be arranged one inrelation to the other, with accurate positioning of the sliding elementtaking place by way of an equalizing compound which is solid when in anoperating state and free-flowing prior thereto, in particular uponassembly, so that the sliding element may uniformly adapt to theassociated slide face.

[0008] Additional features and details of the invention will becomeapparent from the ensuing description of four exemplary embodiments,taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWING

[0009]FIG. 1 is a longitudinal sectional view of a sliding bearingaccording to a first embodiment;

[0010]FIG. 2 is a cross-sectional view on the line II-II of FIG. 1;

[0011]FIG. 3 is a longitudinal sectional view of a sliding bearingaccording to a second embodiment;

[0012]FIG. 4 is a cross-sectional view on the line IV-IV of FIG. 3;

[0013]FIG. 5 is a longitudinal sectional view of a sliding bearingaccording to a third embodiment;

[0014]FIG. 6 is a cross-sectional view on the line VI-VI of FIG. 5;

[0015]FIG. 7 is a longitudinal sectional view of a sliding bearingaccording to a fourth embodiment; and

[0016]FIG. 8 is a cross-sectional view on the line VIII-VIII of FIG. 7.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0017] The following is a description of a first embodiment of theinvention, taken in conjunction with FIGS. 1 and 2. A sliding bearing 1comprises an interior pipe 2 as a first bearing member, having anassociated central longitudinal axis 3, and an exterior pipe 4 as asecond bearing member, having an associated central longitudinal axis 5which coincides with the axis 3. The sliding bearing 1 permits theinterior pipe 2 to be axially and/or radially arranged in relation tothe exterior pipe 4. The pipes 2 and 4 can be structural components of atelescopic unit of several pipes which are disposed successively onewithin the other and which are displaceable one relative to the otherfor example by a spindle drive.

[0018] The exterior pipe 4 encloses a cylindrical interior space 6,which is open at the ends, and it comprises a slide face 7 on itsinside. The interior pipe 2, which is disposed in the exterior pipe 4concentrically thereof, comprises a cylindrical slide face 8 on itsexternal surface. A clearance S_(G) exists between the slide faces 7 and8, which is sufficiently dimensioned for the interior pipe 2 to bepushed into the exterior pipe 4 without any problems. Even though theslide faces 7 and 8 are substantially parallel to each other, worktolerances may nevertheless lead to minor fluctuations.

[0019] The interior pipe 2 comprises at least one encircling annulargroove 9, or two annular grooves as seen in FIG. 1, and by advantageseveral annular grooves 9, which are axially offset from one another,with the axial extension thereof exceeding, in particular considerablyexceeding, the radial depth thereof. A equalizing compound 11 is locatedat the bottom 10 of the annular groove 9; it will be described in detailbelow, taken in conjunction with the description of how to produce thesliding bearing. A sliding band 13 in the form of a sliding/guidingelement is located on the equalizing compound 11, encircling theinterior pipe 2 except for an equalizing gap 12. This sliding band 13,which is located in the annular groove 9, stands out radially from theupper edge of the annular groove 9 and thus from the slide face 8,resting planely and uniformly on the slide face 7. For excellentlyguided displaceability, as frictionless as possible, of the interiorpipe 2 within the exterior pipe 4, provision can be made for some ratherinsignificant, regular guide clearance S_(F) between the outer face ofthe sliding band 13 and the slide face 7. The sliding band 13 consistsof a material of good sliding capability, in particular of plastics.Teflon or plastics mixed with bronze particles are especially preferred.The equalizing compound 11 is an adhesive for fixing the sliding band 13in the associated annular groove 9. The equalizing compound 11 used mayalso be a filling compound without adhesive effect. In this case, thesliding band 13 is held in the position seen in FIG. 1 only by theannular groove 9 and the opposed slide face 7. In the embodimentaccording to FIG. 1, the sliding bearing 1 works as a radial as well asan axial bearing.

[0020] It is also possible to fix the sliding band 13 directly on theinterior pipe 2 without corresponding annular grooves. Further, theannular grooves may run in the axial direction only across part of theaxial length of the sliding band 13, taking up only excess equalizingcompound 11. It is sufficient if the slide face 7, on which the slidingband 13 rests for sliding displacement, possesses only insignificantsurface roughness. The slide face 8 can have a rougher surface. However,it must not touch the opposite slide face 7. In general, only the slideface the sliding band 13 rests on for sliding displacement has to beespecially smooth. This does not apply to the other slide face.

[0021] The following is a description of the manufacture and mode ofoperation of the sliding bearing 1. The interior pipe 2, which isprovided with annular grooves 9 and which is not inside the exteriorpipe 4 prior to assembly, is provided with a free-flowing, pastyequalizing compound 11 that is applied to the bottom 10 of the annulargrooves 9. The compound 11 may be a curable adhesive or a curable resin.Fundamentally, it is also conceivable to use curable compounds withoutadhesive effect. Excess equalizing compound 11 is applied in theprocess. Then a sliding band 13 is placed on the equalizing compound 11in such a way that the sliding band 13 encloses the interior pipe 19with the exception of a equalizing gap 12. Because of the excesscompound 11, the sliding band 13 stands out more than seen in FIG. 1 inthe radial direction. Then the exterior pipe 4 is pushed on thecorrespondingly prepared interior pipe 2, the respective sliding band 13being pressed radially inwards to such an extent that it rests uniformlyand planely on the slide face 7 of the exterior pipe 4. Any excessequalizing compound 11 is pressed into the equalizing gap 12. It is alsopossible that the equalizing compound 11 escapes outwards in thevicinity of the edges of the annular groove 9. A mandrel is used forjoining the two pipes 2 and 4, positioning the pipes 2 and 4 relative toeach other as desired. Once the equalizing compound 11 has cured,accurate fit of the sliding bands 13 in relation to the associated slideface 7 is produced so that the pipes 2, 4 are insertable one into theother by accurate fit.

[0022] The following is a description of a second exemplary embodimentof the invention, taken in conjunction with FIGS. 3 and 4.Constructionally identical parts have the same reference numerals as inthe first embodiment, to the description of which reference is made.Functionally identical parts that differ in construction have the samereference numerals with an a affixed. The essential difference from thefirst embodiment resides in that the annular grooves 9 are not providedon the interior pipe 2, but on the inside of the exterior pipe 4 a sothat also the sliding bands 13 are fixed to the inside of the exteriorpipe 4 a, resting slidingly on the slide face 8 of the interior pipe 2a. As regards the manufacture and mode of operation of the slidingbearing 1 a, reference is made to the explanation of the firstembodiment.

[0023] A third embodiment of the invention will be described below,taken in conjunction with FIGS. 5 and 6. Constructionally identicalparts have the same reference numerals as in the first exemplaryembodiment, to the description of which reference is made. Functionallyidentical parts that differ in construction have the same referencenumerals with a b affixed. The sliding bearing 1 b has substantially thesame structure as the sliding bearing of the first embodiment. Thesliding bands 13 are connected with the interior pipe 2. Uponmanufacture, the sliding bands 13 possess a detachable film 14 outside.Upon assembly of the interior pipe 2 and the still free-flowingequalizing compound 11, the interior pipe 2, together with the slidingbands 13 and the films 14 located thereon, is inserted into the exteriorpipe 4, as seen in FIG. 5. After the equalizing compound 11 has cured,the interior pipe 2 is extracted from the exterior pipe 4 and the films14 are removed. For standard operation, the interior pipe 2 is thenagain pushed into the exterior pipe 4, there being now someinsignificant guide clearance S_(F) between the outside of the slidingbands 13 and the associated slide face 7; this clearance S_(F)corresponds to the thickness of the film and is indispensable for asfrictionless as possible a displacement. In this regard, FIG. 5 does notshow the final state of operation of the sliding bearing 1 b, but anintermediate state in the production of the sliding bearing 1 b with thefilm 14 still in place.

[0024] A fourth embodiment of the invention will be described below,taken in conjunction with FIGS. 7 and 8. Constructionally identicalparts have the same reference numerals as in the first exemplaryembodiment, to the description of which reference is made. Functionallyidentical parts that differ in construction have the same referencenumerals with a c affixed. The exterior pipe 4 c and the interior pipe 2c have a rectancular cross-sectional shape seen in FIG. 8. It is alsopossible to provide other non-circular cross-sectional forms, forexample elliptical cross sections for non-rotatability of the two pipes2 c, 4 c relative to each other to be obtained. The interior pipe 2 ccomprises four slide faces 7 c, on each of which equalizing compound 11and a sliding band 13 placed thereon are provided, reachingsubstantially across the full width of the respective slide face 7 c. Nosliding band 13 is provided in the corner area 15 of the interior pipe 2c. The corner areas 15 serve as an equalizing space for any excessequalizing compound 11. Unlike the first embodiment, the sliding bands13 of the fourth embodiment are not accommodated in annular grooves 9.This is however possible. The non-circular cross-sectional shape of thepipes 2 c and 4 c ensures that these pipes are not displaceableradially, but only axially.

What is claimed is:
 1. A sliding bearing for at least one of axial andradial arrangement of a first bearing member (2; 2 a; 2 c) in relationto a second bearing member (4; 4 a; 4 c), comprising a. a second bearingmember (4; 4 a; 4 c) which has a bearing recess (6) provided with asecond slide face (7; 7 c); b. a first bearing member (2; 2 a; 2 c),which is lodged in the bearing recess (6) and which is mounted in atleast one of an axial and radial fashion, i. the first bearing member(2; 2 a; 2 c) having a first slide face (8; 8 c), which is opposite thesecond slide face (7; 7 c) and spaced therefrom by a clearance S_(G); c.at least one sliding/guiding element (13), which is disposed between thefirst and the second bearing members (2, 4; 2 a, 4 a; 2 c, 4 c) andfixed in relation to one bearing member (2; 4 a; 2; 2 c), for guidanceof a motion of the first relative to the second bearing member (2, 4; 2a, 4 a; 2 c, 4 c); d. an equalizing compound (11), which is disposedbetween the at least one sliding/guiding element (13) and the bearingmember (2; 4 a; 2; 2 c) relative to which is fixed the at least onesliding/guiding element (13), for adaptation of the guide clearanceS_(F) between the at least one sliding/guiding element (13) and theslide face (7; 8; 7; 7 c) that is displaceable in relation thereto, i.the equalizing compound (11) being solid in the operating state of thesliding bearing and free-flowing prior thereto.
 2. A sliding bearingaccording to claim 1, wherein the second bearing member (4; 4 a; 4 c) isa second pipe.
 3. A sliding bearing according to claim 2, wherein thesecond pipe has one of a circular cross-sectional shape and anon-circular cross-sectional shape and a rectangular cross-sectionalshape.
 4. A sliding bearing according to claim 2, wherein the firstbearing member (2; 2 a; 2 c) is a first pipe.
 5. A sliding bearingaccording to claim 4, wherein the cross-sectional shape of the firstpipe is adapted to the cross-sectional shape of the second pipe so thata clearance S_(G) exists between the first pipe and the second pipe. 6.A sliding bearing according to claim 1, wherein the sliding/guidingelement (13) is a sliding band (13).
 7. A sliding bearing according toclaim 6, wherein the sliding band (13) has a substantially rectangularcross-sectional shape.
 8. A sliding bearing according to claim 6,wherein the sliding band (13) encircles the first bearing member (2; 2a; 2 c) at least partially, forming at least one equalizing gap (12). 9.A sliding bearing according to claim 6, wherein the sliding band (13) isconnected to at least one of the first bearing member (2; 2 c) and thesecond bearing member (4; 4 a; 4 c).
 10. A sliding bearing according toclaim 6, wherein the sliding band (13) consists of plastics.
 11. Amethod of manufacturing the sliding bearing for at least one of axialand radial arrangement of a first bearing member in relation to a secondbearing member, comprising the following steps: a. providing a secondbearing member with a bearing recess that comprises a second slide face,and a first bearing member which is insertable in the bearing recess,having a first slide face that is allocated to the second slide face; b.applying a curable equalizing compound, which is free-flowing whenworked, to a section of a slide face and to the sliding band; c. placingthe sliding band on the equalizing compound; d. inserting the firstbearing member into the bearing recess of the second bearing member sothat the at least one sliding band rests uniformly and planely on theopposite slide face and the excess equalizing compound is squeezed intoequalizing areas that are provided therefor; e. curing the equalizingcompound.
 12. A method according to claim 11, wherein the at least onesliding band applied to the equalizing compound comprises a detachablefilm on its outside; and in that after curing of the equalizingcompound, the first bearing member is withdrawn from the bearing recessand the film is removed, whereby a pre-determined guide clearance S_(F)is produced between the outside of the at least one sliding band and theopposite slide face and/or the excessive equalizing compound isprevented from adhering to the slide face.
 13. A method according toclaim 11, wherein for insertion of the first bearing member into thesecond bearing member, use is made of a positioning device which holdsthe first bearing member in a pre-dertermined position relative to thesecond bearing member until the equalizing compound has cured.
 14. Asliding bearing according to claim 1, wherein at least one of the firstslide face (8; 8 c) and the second slide face (7; 7 c) possesses littlesurface roughness for displacement thereon of the sliding/guidingelement (13).